Pressure dependence of hydrogen-induced amorphization in C14 Laves phase NdMn2

Hydrogen Storage In A Novel Destabilized Hydride System, Ca2SiHx: Effects of Amorphization

“…For example, it has been shown that HIA occurs only in compounds with an atomic size ratio larger than 1.37 among C15 Laves AB 2 phases. Besides, some C15 and C14 Laves phases amorphize only above a critical hydrogen pressure. , The Ca 2 Si phase does not belong to any of the above structure families. Yet, its structure (C37 compound, Co 2 Si-type, space group Pnma ) is similar to that of the C23 compounds (PbCl 2 -type, space group Pnma ) with the same A 2 B stoichiometries (A = hydride-forming element; B = non-hydride-forming element).…”

“…, B = Al, Ga, In, Sn), and L1 2 (A 3 B phases; e.g., A = Zr; B = Al, In, Rh, etc . ). − However, the formation of (possibly nanoparticulate) amorphous phases upon hydrogenation have not been observed in any alloys with a Co 2 Si-type structure.…”

Hydrogen-induced and A-site substitution-dependent structural properties of AB2-type (Ho1−xAx)Co2–hydrogen system (A=Mm and Ti)

“…Since (Ho, Mm) atoms having large negative heat of mixing with hydrogen, the hydrogen atoms can stay more stable in the (2R2M)-sites than in (1R3M)-sites [27,32]. Therefore, it is suggested that the first and the second endothermic peaks are due to hydrogen desorption from the tetrahedral sites surrounded by [1(Ho,Mm) [15][16][17]. In addition, from the XRD and DSC studies of RCo 2 -H systems [4,6,13,[15][16][17], it is concluded that the first exothermic transition is due to the transformation from the crystalline hydride to the amorphous hydride and second exothermic transition is due to the decomposition of amorphous hydride.…”

“…Among these intermetallics, HIA in the Laves phase RM 2 (R = a rare earth metal, M = Fe, Co, Ni and Mn) is particularly interesting and a lot of investigations have been employed to confirm HIA [6][7][8][9][10][11][12]. The formation of amorphous hydrides and decomposition into constituent hydrides greatly depend on the hydrogenation temperature [4,6,9,13], the hydrogen pressure [14][15][16][17] and the type of rare earth or transition metal present in the RM 2 alloy [1][2][3][4]8,10,11,18,19]. Further, there are a few of the investigations on the HIA and decomposition of the pseudobinary and ternary alloys, in which the HIA mainly depends on the substitution of the third element in either of the sites of binary Laves phase RM 2 alloys [20][21][22][23][24][25].…”

Phase decomposition and electrochemical properties of single phase La1.6Mg0.4Ni7 alloy

“…It has been found that, in PuNi 3 -type LaNi 3 alloys, the reduction of its irreversible capacity is due to immediately hydrogen-induced amorphization (HIA) in the [A 2 B 4 ] slabs [17]. Besides, the HIA is a character of Laves (C14 or C15) phase that the phase transforms to amorphous state after hydrogen absorption [18,19]. For Ce 2 Ni 7 -type phase of which the [A 2 B 4 ] slabs are C14 Laves structure, attenuation may also related to the [A 2 B 4 ] slabs, but investigation on this aspect is still a vacancy.…”